The invention relates to vehicle roofs having a sunroof apparatus for closing and selectively, at least partially, opening an opening that extends through the fixed roof of a motor vehicle. In particular, the invention pertains to a vehicle roof sunroof apparatus wherein the roof opening is covered by two movable roof panels which, in their position closing the vehicle roof opening, lie one behind the other and wherein, for at least partially uncovering the roof opening, the front panel is upwardly tiltable and is rearwardly displaceable.
From German Pat. No. 19 46 161, a vehicle roof of this general type is known that has a pair of movable cover panels which, in the closed position thereof, lie one behind the other in the longitudinal direction of the vehicle. These cover panels are displaceable, from their position closing the opening through the fixed vehicle roof, in a number of different modes for purposes of partially uncovering the roof opening. In a first mode, the front cover panel is upwardly tiltable to provide ventilation of the vehicle interior, and with the front panel in this upwardly tilted mode, optionally, the rear panel may be lowered and slidably retracted underneath the fixed roof structure so as to expose the rear half of the roof opening. Alternatively, this sliding retraction of the rear cover panel may be carried out while the front cover panel remains in its lowered position closing the front half of the roof opening or, selectively, the lowered front panel can be slid rearwardly into the position formerly occupied by the rear panel in its closed position, thereby the expose the front half of the vehicle roof opening. However, such a vehicle sunroof apparatus is subject to disadvantages which limit the size of the roof opening that can be provided in the fixed roof structure and the extend to which it can be exposed. That is, since the rear panel must be retracted underneath the fixed roof surface, the extent to which the opening through the fixed roof structure can be rearwardly extended is thereby limited. This disadvantage is further compounded by the fact that the movable cover panels can never be placed in a condition which substantially completely exposes the entire roof opening.
An upwardly tiltable sunroof apparatus is known from U.S. Pat. No. 4,142,761 which has a single cover panel that can selectively be tilted upwardly or totally removed. However, since a person has to be able to lift off the cover panel and store it, for example, in the vehicle trunk, limitations upon the size of the cover panel, and therefore, upon the size of the roof opening, are accordingly imposed.
Another single panel sunroof apparatus is known from British Pat. No. 2,122,250 which is of the so-called "spoiler" roof type, wherein the cover panel is upwardly tiltable and then rearwardly slidable to a position in which the rear portion of the cover panel is disposed above the rest area of the fixed roof structure of the motor vehicle, thereby substantially completely exposing the opening in the vehicle roof. However, if the size of the portion of the cover panel that is cantilevered above the rear fixed roof area of the vehicle is too large, it will be subjected to excessively high loads when the vehicle is driven at high speeds. Thus, even with a spoiler roof of this type, restrictions are imposed upon the size of the roof opening that can be provided.
As a result, even though it is desirable to have a roof opening in a vehicle that is as large as possible and can be exposed to the greatest extend possible, since a function of a sunroof apparatus is for ventilation and lighting, sunroof apparatus of vehicle roofs as known to date have, effectively, been unable to permit more than one-half of the full length of the roof to be opened.